在Docker上运行的Java App中写入文件

Question

背景

我正在尝试创建一个编译器Web服务,因此用户可以发布用我编写的某种语言编写的代码,然后它将编译,运行并返回打印结果.我的第二次迭代涉及使用Docker镜像来隔离POST进入我正在运行的Web服务器的代码的运行.

问题

我试图将发布的代码写入文本文件以在其上运行我的编译器,但我的编译器尝试创建文件失败.我的文件路径应该是正确的,我的其他测试路由正常.这是我正在尝试运行的一些演示代码,但失败了:

try (Writer writer = new BufferedWriter(new OutputStreamWriter(
                new FileOutputStream("/raw/compile-source.slacc"), "utf-8"))) {
            writer.write(req.body());
        }

在我用来启动它的Dockerfile中,我创建了/ raw目录,如果重要的话.我想象Docker不希望Java进程创建任意文件.有什么想法吗？下面是我的Dockerfile.

我的Dockerfile

FROM java:8

# Install maven
RUN apt-get update
RUN apt-get install -y maven

WORKDIR /code

# Prepare by downloading dependencies
ADD pom.xml /code/pom.xml
RUN ["mvn", "dependency:resolve"]
RUN ["mvn", "verify"]

# Adding source, compile and package into a fat jar
ADD src /code/src
RUN ["mvn", "package"]

CMD ["java", "-version"]

CMD ["mkdir", "/raw"]
CMD ["mkdir", "/classfiles"];
CMD ["mkdir", "/out"];
EXPOSE 4567
CMD ["mvn", "exec:java"]

Answer 1

我把 CMD 和 RUN 搞混了。我只需要最后的

mvn exec:java

在 CMD 块中，但其他块需要运行。这是我的最终输出。我还省略了获取 scala。:)

FROM java:8

# Install Scala
ENV SCALA_HOME /usr/local/share/scala
ENV PATH $PATH:$SCALA_HOME/bin

ENV SCALA_VERSION 2.11.8

RUN wget --quiet http://downloads.lightbend.com/scala/$SCALA_VERSION/scala-$SCALA_VERSION.tgz && \
tar -xf scala-$SCALA_VERSION.tgz && \
rm scala-$SCALA_VERSION.tgz && \
mv scala-$SCALA_VERSION $SCALA_HOME

# Install maven
RUN apt-get update
RUN apt-get install -y maven

WORKDIR /code

# Prepare by downloading dependencies
ADD pom.xml /code/pom.xml
RUN ["mvn", "dependency:resolve"]
RUN ["mvn", "verify"]

# Adding source, compile and package into a fat jar
ADD src /code/src
RUN ["mvn", "package"]

RUN ["java", "-version"]

RUN ["mkdir", "/raw"]
RUN ["chmod", "a+w", "/raw"]
RUN ["mkdir", "/classfiles"];
RUN ["mkdir", "/out"];
EXPOSE 4567
CMD ["mvn", "exec:java"]

感谢大家的回复和帮助我。